For Tc sulfur colloid gastric emptying studies, what is the organ of interest that receives the highest radiation dose?

• A. Small intestine
• B. Stomach
• C. Liver
• D. Gallbladder

Answer: (B)

In Tc sulfur colloid gastric emptying studies, the stomach is indeed the organ of interest that receives the highest radiation dose. This is due to the nature of the sulfur colloid radiopharmaceutical, which is primarily designed to assess gastric function and transit time.

When administered, the radiopharmaceutical accumulates in the gastric mucosa, allowing for detailed imaging and quantification of gastric emptying. Since the stomach is where the substance is initially localized and where the assessment begins, it naturally receives the highest radiation dose during this process. This dose is important for diagnostic purposes as it helps in evaluating the gastric emptying rate, which is critical for identifying conditions like gastroparesis or other gastric motility disorders.

The other organs listed, while they may receive some level of exposure, are less significant in the context of the study, as the primary focus is on the stomach's role in processing the radiopharmaceutical. The different anatomy and physiological functions of the small intestine, liver, and gallbladder explain why they do not receive as high a radiation dose in this specific scan.